Franklin County, IA Insulation Payback
Franklin County, IA: what topping up your attic actually costs
DOE classifies Franklin County as climate zone 6, cold — a real winter that drives most of the annual energy bill here. Its recommended attic R-value for bare joists is R-60. For an attic around 1,000 square feet, closing the gap from R-2 to R-60 costs around $3,480 and saves an estimated $2,083 a year — payback in roughly 1.7 years. That's about as fast as attic paybacks get.
The breakdown behind the number
The estimated savings split roughly $1,969/year heating, $114/year cooling. Out of every 100 US counties tracked here, Franklin County's savings potential beats roughly 86 of them. Within zone 6 specifically, it ranks 310th of 459 counties by estimated savings. Iowa averages $1,985/year across the counties tracked here; Franklin County comes in 5% higher.
The climate data behind this
The heating and cooling degree days behind this estimate — 7,363 HDD and 712 CDD (base 65°F, 1991-2020 normals) — come from HAMPTON, IA US, the nearest NOAA station with published normals, 3.8 miles from Franklin County's center. By total degree days, Franklin County sits at the 87th percentile nationally. Franklin County falls in DOE's moisture regime A (humid), a detail that affects vapor-barrier recommendations more than the R-value target itself.
The smaller top-up scenario
If Franklin County's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-49. That smaller top-up costs around $2,280 and saves an estimated $304/year — payback about 7.5 years. That is a solid payback as home upgrades go.
Getting it done in Franklin County
Get more than one quote before committing. Attic access and any needed air sealing move the price around, and most contractors won't take a job below roughly $600 regardless of size - worth asking upfront given Franklin County's estimated $2,083/year on the line.
Nothing here is a guess
Every figure on this page traces to DOE/IECC climate zones and NOAA degree-day normals, documented in the methodology guide. The guide to what R-value actually means explains why R-60 is the target here specifically.